const int ultrasonicSensorPin = 2; 
const int ledPin = 13;  

void setup() {
  Serial.begin(9600); 
  pinMode(ultrasonicSensorPin, INPUT);  
  pinMode(ledPin, OUTPUT);
}

void loop() {  
  int distance = getDistance();
    
  Serial.print("Distance: ");
  Serial.println(distance);
  
  if (distance < 30) {
    digitalWrite(ledPin, HIGH);
  } 
  else {    
    digitalWrite(ledPin, LOW);
  }
  delay(1000);
}

int getDistance() {
  return random(5, 100); 
}